Primer's and Flash hole's

[Jmac00]

why does a smaller flash hole with a smaller primer make a cartridge more accurate?

Lapua is coming out with a 6.5 Creedmoor case. They claim the 1.5mm flash hole with a small rifle primer will make the cartridge better than the standard 2mm FH and Large rifle primer?

can anyone explain why that is.....thanx

 

[Phauxtoe]

Wow I thought this is gonna be a totally different thread

 

[Jmac00]

Wow I thought this is gonna be a totally different thread

don't go there

 

[Phauxtoe]

Time for some fake science !
Could a big flash whole cause turbulence with in the case as the charge is going off ?

 

[Jmac00]

i would think a large flash hole would create a more even burn throughout? pushing the projectile down the barrel more consistently? But IDK, thats why I asked

 

[Phauxtoe]

Of course they are a company trying to sell more products
so maybe it's a sales gimmick ?

 

[Darth]

I think it's sumadat reloading placebo.

Seriously, individuals and companies get a little nuts-o when it comes to squeezing out "accuracy." To the point it's well beyond not only human error, but human possibility.

It's like the people that weigh each bullet. Ok. And each case. Err...ok. And each charge, primer, what they had for breakfast...

There is a limit folks.

 

[Phauxtoe]

What about altitude and humidity when you are reloading?

 

[Mosinitis]

Cases with a small primer hold up to pressure better than cases with a large primer, all else being equal. This makes it possible for hotter loads, more velocity, better ballistics.

 

[MilesTeg]

I'm not sure there's much a of a difference between small and large performance wise. You light be able squeeze a few fps but 99.99% that would make little to no difference on the accuracy of the round. It might be due to the fact we're in a little bit of a primer shortage so it allows people the option to load what the have on hand.

Now if you want talk about why different brands of primers do better than others or bench rest vs. normal primers. That lies with how consistently they ignite.

If your going for extreme accuracy you can't switch out primers and expect the same results. When ever you switch out to a different primer they will rework up the load to meet their standards. I have seen bench rest shooters do this for the same primer but from a different lot.

 

[Jmac00]

interesting replies, Thank you for the insight

 

[Mosinitis]

6.5 Creedmoor came from the world of long range highpower competition, where wind is a huge factor. The reason for small primer is more meat in the area where cases fail due to pressure. It will also take more reloads before the primer pocket gets loose, for the same reason. Accuracy is not the only factor, bucking the wind is more important at longer ranges. Speed becomes very important.